The present invention relates to electrical fuses and fuse blocks such as are used in automobiles, trucks and in a wide variety of electrical and electronic equipment.
Electrical fuses for many medium power applications have a non-conductive housing, a fusible link in the housing, and a pair of electrical contacts extending from external of the housing into electrical contact with opposite sides of the fusible link. Typical fuses of the prior art have the housing translucent for permitting visual inspection of the fusible link. Other fuses have elements that move or change color when the fuse is blown. However, in many situations it is impractical to visually monitor the fuses, such as when a large number of fuses are connected in different circuit portions of a system, and when only limited ambient light is available for inspecting the fuses.
It is also known to provide illuminated indicia of fuse failure as disclosed, for example in U.S. Pat. Nos. 4,382,225 to Peltz and 4,875,322 to Shumway. U.S. Pat. No. 5,300,913 to Liston also discloses light indicators being connected across ferrules of cartridge fuses with reference to U.S. Pat. Nos. 3,432,789 and 3,457,535.
The illuminated fuse fault indicators of the prior art exhibit one or more of the following disadvantages:
1. They are ineffective for use with blade contact fuses and in low voltage DC circuits and/or circuits having very low resistance loads; PA1 2. They are unsuitable in that they are undesirably bulky and/or they require impractical additional wiring in many applications; PA1 3. They are unreliable in that they are subject to damage in ordinary handling; PA1 4. They are unsafe in that they have exposed conductors that are subject to shorting; and PA1 5. They are undesirably expensive to produce.
Thus there is a need for an illuminating fuse fault indicator that avoids the disadvantages of the prior art.